Revert "Merge CMTEventData and ValuatorTracker"

ui/base/x/valuators.h

+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef UI_BASE_X_VALUATORS_H_
+#define UI_BASE_X_VALUATORS_H_
+
+#include "base/basictypes.h"
+#include "ui/base/ui_export.h"
+
+template <typename T> struct DefaultSingletonTraits;
+
+typedef union _XEvent XEvent;
+
+namespace ui {
+
+// A valuator is not reported in an XEvent if it hasn't changed from the
+// previous event from the same device. As a result, it is necessary to track
+// the last reported valuator values for a specific device.
+// Right now, this is only used to keep track of valuators for events coming in
+// from touch-devices, but it can be used for other devices as well.
+class UI_EXPORT ValuatorTracker {
+ private:
+  ValuatorTracker();
+  ~ValuatorTracker();
+
+ public:
+  // Define the valuators following the Multi-touch Protocol.
+  enum Valuator {
+    VAL_TOUCH_MAJOR = 0,   // Length of the touch area.
+    VAL_TOUCH_MINOR,       // Width of the touch area.
+    VAL_ORIENTATION,       // Angle between the X-axis and the major axis of the
+                           // touch area.
+    VAL_PRESSURE,          // Pressure of the touch contact.
+
+    // NOTE: A touch event can have multiple touch points. So when we receive a
+    // touch event, we need to determine which point triggered the event.
+    // A touch point can have both a 'Slot ID' and a 'Tracking ID', and they can
+    // be (in fact, usually are) different. The 'Slot ID' ranges between 0 and
+    // (X - 1), where X is the maximum touch points supported by the device. The
+    // 'Tracking ID' can be any 16-bit value. With XInput 2.0, an XI_Motion
+    // event that comes from a currently-unused 'Slot ID' indicates the creation
+    // of a new touch point, and any event that comes with a 0 value for
+    // 'Tracking ID' marks the removal of a touch point. During the lifetime of
+    // a touchpoint, we use the 'Slot ID' as its identifier. The XI_ButtonPress
+    // and XI_ButtonRelease events are ignored.
+#if !defined(USE_XI2_MT)
+    VAL_SLOT_ID,           // ID of the finger that triggered a touch event
+                           // (useful when tracking multiple simultaneous
+                           // touches)
+#endif
+    // NOTE for XInput MT: 'Tracking ID' is provided in every touch event to
+    // track individual touch. 'Tracking ID' is an unsigned 32-bit value and
+    // is increased for each new touch. It will wrap back to 0 when reaching
+    // the numerical limit.
+    VAL_TRACKING_ID,       // ID of the touch point.
+
+    // Kernel timestamp from touch screen (if available).
+    VAL_TOUCH_RAW_TIMESTAMP,
+
+    VAL_LAST_ENTRY
+  };
+
+  // Returns the ValuatorTracker singleton.
+  static ValuatorTracker* GetInstance();
+
+  // Extract the Valuator from the XEvent. Return true and the value is set
+  // if the Valuator is found, false and value unchanged if the Valuator
+  // is not found.
+  bool ExtractValuator(const XEvent& xev, Valuator val, double* value);
+
+  // Normalize the Valuator with value on deviceid to fall into [0, 1].
+  // *value = (*value - min_value_of_tp) / (max_value_of_tp - min_value_of_tp)
+  // Returns true and sets the normalized value in|value| if normalization is
+  // successful. Returns false and |value| is unchanged otherwise.
+  bool NormalizeValuator(unsigned int deviceid, Valuator val, double* value);
+
+  // Extract the range of the Valuator. Return true if the range is available
+  // and written into min & max, false if the range is not available.
+  bool GetValuatorRange(unsigned int deviceid,
+                        Valuator val,
+                        double* min,
+                        double* max);
+
+  // Sets up the internal bookkeeping of the valuator information. It currently
+  // does this for touch devices only.
+  void SetupValuator();
+
+ private:
+  // Requirement for Singleton.
+  friend struct DefaultSingletonTraits<ValuatorTracker>;
+
+  static const int kMaxDeviceNum = 128;
+
+  // Index table to find the valuator for the Valuator on the specific device
+  // by valuator_lookup_[device_id][valuator]. Use 2-D array to get fast
+  // index at the expense of space. If the kMaxDeviceNum grows larger so that
+  // the space waste becomes a concern, the 2D lookup table can be replaced by a
+  // hash map.
+  signed char valuator_lookup_[kMaxDeviceNum][VAL_LAST_ENTRY];
+
+  // Index table to find the min & max value of the Valuator on a specific
+  // device.
+  double valuator_min_[kMaxDeviceNum][VAL_LAST_ENTRY];
+  double valuator_max_[kMaxDeviceNum][VAL_LAST_ENTRY];
+
+  // Table to keep track of the last seen value for the specified valuator for
+  // a device. Defaults to 0 if the valuator was not specified in an earlier
+  // event.
+  double last_seen_valuator_[kMaxDeviceNum][VAL_LAST_ENTRY];
+
+  DISALLOW_COPY_AND_ASSIGN(ValuatorTracker);
+};
+
+}  // namespace ui
+
+#endif  // UI_BASE_X_VALUATORS_H_